The group mixed fentanyl and its analog carfentanyl with bulking agents at an industrial unit in Leeds before selling them on sites like Alpha Bay under the name “UKBargins,” according to the National Crime Agency (NCA).

It’s unclear how they were brought to justice, although the trio were arrested in April 2017, less than three months before the Alpha Bay and Hansa takedowns. When policed raided the unit, a laptop was found displaying the UKBargins store on Alpha Bay.

Childs was apparently caught on CCTV in a Post Office mailing hundreds of packages of drugs to customers worldwide including as far afield as Australia, Argentina and Singapore.

Between December 2016 and April 2017 the three are said to have turned over £163,474 — selling 2853 items to 443 customers worldwide including 172 in the UK.

During the raid, 2.6kg of carfentanyl was recovered including a packet of 440g pure carfentanyl, the largest such seizure of its kind in Europe, according to the NCA.

The drug is said to be 10,000-times more potent than morphine, while fentanyl is up to 10-times stronger. Both have been linked to countless deaths over recent years.

“Fentanyl and carfentanyl are extremely potent, the latter having no medical uses for humans. Not only is it potentially lethal for those taking it, these drugs pose a serious danger to all those that come into contact with them, be that first responders like law enforcement and medical staff, or in this case, postal staff,” said NCA senior investigating officer, Graham Roberts.

“The lengthy jail terms handed down to them today are a reflection on their dangerous and careless actions.”